Term Explanation:

 

I. Definition and Functions of Routers

 

A router is a network device primarily used to connect different networks and forward data packets. Its core function is to determine the best transmission path for data packets based on network layer address information (typically IP addresses). Routers can connect multiple networks, including Local Area Networks (LANs) and Wide Area Networks (WANs), and can route data using various protocols (such as BGP, OSPF, etc.).

 

The main functions of routers include:

1. Packet Forwarding: Selecting the best path based on the destination address to send data packets from the source to the destination.

Key note: Network Processing Engine(NPU): Also known as Hardware Acceleration, can be understood literally as a chip specifically designed for processing data packet forwarding. Its main function is to receive data packets and quickly forward them according to their addresses, much like a conveyor for delivering packages. Furthermore, it is solely responsible for packet forwarding and cannot handle other complicated tasks like IDS, DPI, QoS, and Bandwidth Control.

On the other hand, the CPU can be used to process a variety of different rules. When it processes IDS, DPI, QoS, Bandwidth Control, or other features, it usually does not send it to the NPU for forwarding. It will forward directly via the CPU. But when the CPU is forwarding, it will require the LINUX (kernel) network stack. This does not perform well under (forwarding) heavy traffic and the CPU will throttle due to this.

The CPU is like the human brain; it can perform arithmetic operations, and engage in logical reasoning. In contrast, the NPU is more like a calculator, capable only of performing basic arithmetic operations. However, due to its specialized design, the NPU operates with high efficiency and consumes less power.
2. Network Address Translation (NAT): Converting private network addresses to public addresses for internet access.
3. Firewall Functionality: Providing a certain level of security by setting up Access Control Lists (ACLs) to prevent unauthorized access.
4. VPN Support: Establishing secure connections between different networks to protect the privacy of data transmission.

 

 

II. Definition and Functions of Switches

 

A switch is a device that focuses more on internal communications within a Local Area Network (LAN). It primarily forwards data among devices within the same network. It operates at the data link layer (Layer 2) and identifies and processes data frames using MAC addresses.

 

The main functions of switches include:

1. Frame Forwarding: Identifying the destination device based on the MAC address and quickly forwarding the data frame to the target device.

 

2. Creating Virtual Local Area Networks (VLANs): Dividing large LANs into smaller networks to enhance management efficiency and security.
3. Traffic Management: Ensuring that bandwidth requirements for critical applications are met through Quality of Service (QoS) mechanisms.
4. Broadcast Control: Reducing broadcast storms in the network to improve overall performance.

 

III. Differences Between Routers and Switches

 

Although routers and switches both play critical roles in networks, their functions and application scenarios differ.

 

1. Operating Layer:

Routers operate at the network layer (Layer 3) and primarily handle IP addresses.
Switches operate at the data link layer (Layer 2) and primarily handle MAC addresses.

 

2. Functional Focus:

Routers are used to connect different networks and route and forward data packets.
Switches are used to connect devices within the same network, facilitating the exchange and forwarding of data frames.

 

3. Number of Devices:

Routers are typically used to connect a limited number of networks.
Switches can connect a large number of endpoint devices such as computers and printers.

 

4. Security:

Routers have stronger security features, such as firewalls and VPN support.
Switches mainly rely on network-layer security management.

 

IV. Conclusion

 

Routers and switches are fundamental components of modern networks. Routers are responsible for connecting different networks and ensuring smooth data flow between wide area networks and local area networks, while switches optimize communication among devices within a local area network, enhancing overall network performance and efficiency. Understanding the functions and differences between the two is crucial for network design and management. By properly configuring and using routers and switches, one can achieve an efficient and secure network environment.